Sahih Muslim Book 8 Hadith 3373

Abu Sa'id al-Khudri (Allah be pleased with him) reported: We took women captives, and we wanted to do 'azl with them. We then asked Allah's Messen- ger (Peace be upon him) about it, and he said to us: Verily you do it, verily you do it, verily you do it, but the soul which has to be born until the Day of judg- ment must be born.